CN115460518A

CN115460518A - Casing of sound generating device, sound generating device and electronic equipment

Info

Publication number: CN115460518A
Application number: CN202211112706.8A
Authority: CN
Inventors: 周厚强; 王婷; 李春
Original assignee: Goertek Inc
Current assignee: Goertek Inc
Priority date: 2022-09-14
Filing date: 2022-09-14
Publication date: 2022-12-09
Anticipated expiration: 2042-09-14

Abstract

The invention discloses a shell of a sound generating device, the sound generating device and an electronic device, wherein at least one part of the shell is a microcellular foam shell, the raw material of the microcellular foam shell comprises engineering plastic materials, the microcellular foam shell is an integrally formed part formed by foaming and injection molding the raw material, and the microcellular foam shell comprises a first surface layer, a core layer and a second surface layer which are sequentially stacked; wherein the first skin layer and the second skin layer have no pore canal or the pore canal in the first skin layer and the second skin layer has pore diameters less than 0.5 mu m, the core layer has a micropore foaming structure, the micropore foaming structure is a closed pore foaming structure with pores, the diameters of the pores are 0.5 mu m-30 mu m, and the opening rate of the pores on the core layer is less than 10%. The shell of the sound generating device disclosed by the invention can meet the requirements of the sound generating device on reliability, and can also meet the requirements of waterproof and air-permeable performance and light weight.

Description

Casing of sound generating device, sound generating device and electronic equipment

Technical Field

The present invention relates to the field of electroacoustic technologies, and in particular, to a housing of a sound generating device, a sound generating device using the housing, and an electronic device using the sound generating device.

Background

With the development of the electroacoustic technology field, electroacoustic devices are gradually developing towards the direction of lightness, thinness, intellectualization, high power and high frequency.

The traditional loudspeaker shell is usually prepared by adding a glass fiber reinforced material into a PC (polycarbonate) material and performing common injection molding, however, the glass fiber material has a poor reinforcing effect on the PC material, for example, when the flexural modulus of the loudspeaker shell needs to reach 5GPa, more than 20wt% of glass fiber needs to be added, and the addition amount is large. And the density of the glass fiber is approximately 2.5g/cm ³ ～2.8g/cm ³ The density of the PC material is approximately 1.2g/cm ³ It can be seen that the density of the glass fibers is much higher than that of the PC resin. Along with the increase of the addition amount of the glass fiber, the density of the loudspeaker shell is also larger and larger, so that the weight of the loudspeaker shell is larger, the overall weight of the electronic equipment is overlarge, and the use experience of consumers is influenced.

In addition, after the glass fiber is added into the PC material, the toughness of the PC material is reduced, so that the prepared loudspeaker shell is easy to crack and fail in a drop reliability test.

Therefore, a new technical solution is needed to meet the requirements of light weight, high toughness, impact strength, reliability, etc.

Disclosure of Invention

An object of the present invention is to provide a casing of a sound generating device, which can solve at least one of the technical problems of heavy weight, poor reliability and the like of the casing made of PC material in the conventional art.

The invention also aims to provide a sound production device consisting of the shell and the sound production single body.

It is a further object of the present invention to provide an electronic device including the above sound emitting apparatus.

In order to achieve the above object, the present invention provides the following technical solutions.

According to the shell of the sound generating device in the embodiment of the first aspect of the present invention, at least one part of the shell is a microcellular foam shell, the raw material of the microcellular foam shell comprises an engineering plastic material, the microcellular foam shell is an integrally formed part formed by foaming and injection molding the raw material, and the microcellular foam shell comprises a first skin layer, a core layer and a second skin layer which are sequentially stacked;

wherein the pore size of the pores in the first and second skin layers is less than 0.5 μm,

the core layer is of a microporous foaming structure, the microporous foaming structure is of a closed-cell foaming structure with cells, the diameters of the cells are 0.5-30 microns, and the opening rate of the cells on the core layer is less than 10%.

According to some embodiments of the invention, the engineering plastic material comprises at least one of poly 4 methyl-1-pentene, polypropylene, syndiotactic polystyrene, PA66, PA6, PA68, PA610, PA612, PA9, PA1010, PA1012, PA11, PA12, PA1212, PA1313, PPA, PEI polycarbonate, polyoxymethylene, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyarylate, polyetheretherketone, liquid crystal polymer.

According to some embodiments of the invention, the feedstock further comprises a reinforcing agent comprising at least one of glass fibers, carbon fibers, basalt fibers, and polymer fibers.

According to some embodiments of the invention, the reinforcing agent is present in an amount of 10wt% to 40wt% based on the total weight of the feedstock.

According to some embodiments of the invention, the feedstock further comprises a nanofiller comprising at least one of silica, carbon black, clay, carbon nanotubes, calcium carbonate, cellulose, montmorillonite, alumina, graphene oxide, talc, mica powder, kaolin, wollastonite, diatomaceous earth, titanium dioxide.

According to some embodiments of the invention, the largest dimension of the outer contour of the nanofiller is ≦ 3 μm.

According to some embodiments of the invention, the nanofiller is present in an amount ranging from 0.1wt% to 3wt% based on the total weight of the feedstock.

According to some embodiments of the invention, the microcellular foamed casing has a density of 0.8g/cm ³ ～1.2g/cm ³ 。

According to some embodiments of the invention, the microcellular foamed casing has a flexural modulus of 3GPa or more.

According to some embodiments of the invention, the microcellular foamed housing has a heat distortion temperature of 130 ℃ or more.

According to some embodiments of the present invention, the case includes a first sub-case and a second sub-case, the first sub-case is bonded to or integrally injection-molded with the second sub-case, the first sub-case is formed as the microcellular foamed case, and the second sub-case is manufactured by at least one of steel, aluminum alloy, copper alloy, titanium alloy, PP and a modified material thereof, PA and a modified material thereof, PET and a modified material thereof, PBT and a modified material thereof, PPs and a modified material thereof, PEI and a modified material thereof, PEEK and a modified material thereof, PEN and a modified material thereof, PPA and a modified material thereof, PC and a modified material thereof, SPS and a modified material thereof, TPX and a modified material thereof, POM and a modified material thereof, and LCP and a modified material thereof.

A sound emitting device according to an embodiment of the second aspect of the present invention includes the housing of any one of the sound emitting devices described above.

An electronic device according to a third embodiment of the present invention includes the sound emitting apparatus according to the above-described embodiments.

According to the shell of the sound generating device provided by the embodiment of the invention, the integrally formed microporous foaming shell with the three-layer structure is arranged, so that the waterproof and breathable effects are achieved by utilizing the characteristics that the first skin layer and the second skin layer have no pore or have small pore diameters, and the weight of the shell is reduced by utilizing the core layer with the microporous foaming structure, so that the shell is light.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic structural diagram of a sound generating device according to an embodiment of the present invention;

figure 2 is a partial schematic view of a cross-section of a microcellular foam shell according to an embodiment of the present invention.

Reference numerals

A sound generating device 100;

a housing 10; an upper case 11; a first skin layer 111; a core layer 112; a second skin layer 113; a lower case 12;

the sounding unit 20.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

First, the housing 10 of the sound generating device 100 according to the embodiment of the present invention will be described in detail with reference to the drawings. The sound generating apparatus 100 may be a speaker module.

As shown in fig. 1 and fig. 2, in the casing 10 of the sound generating apparatus 100 according to the embodiment of the present invention, at least a portion of the casing 10 is a microcellular foam casing, raw materials of the microcellular foam casing include engineering plastic materials, the microcellular foam casing is an integrally molded part formed by foaming and injection molding the raw materials, and the microcellular foam casing includes a first skin layer 111, a core layer 112, and a second skin layer 113, which are sequentially stacked.

Specifically, the pore diameter of the pore channels in the first skin layer 111 and the second skin layer 113 is less than 0.5 μm, the core layer 112 has a microcellular foam structure, the microcellular foam structure is a closed cell foam structure having cells, the diameter of the cells is 0.5 μm to 30 μm, and the opening rate of the cells on the core layer 112 is less than 10%.

In other words, at least a portion of the casing 10 of the sound generating device 100 of the present invention is formed of a microcellular foamed casing, which may be prepared from raw materials including engineering plastic materials through a microcellular foamed injection molding process, and which is an integrally molded part. The engineering plastic material has excellent comprehensive performance, for example, the engineering plastic material has the advantages of high rigidity, high mechanical strength, good heat resistance, good electrical insulation and the like, and can be used in harsh chemical and physical environments for a long time. When the microcellular foam shell is processed and prepared, engineering plastic materials in the form of matrix resin can be adopted, so that the charging and processing are convenient.

In addition, the integrally molded microcellular foam housing of the present invention has a three-layer structure of the first skin layer 111, the core layer 112, and the second skin layer 113, respectively. The first skin layer 111, the core layer 112, and the second skin layer 113 are sequentially stacked, that is, the microcellular foam housing includes two skin layers, the first skin layer 111 and the second skin layer 113, respectively, and one core layer 112, with the core layer 112 disposed therebetween.

It should be noted that the microcellular foam shell is an integrally formed part formed by microcellular injection molding of raw materials, that is, the first skin layer 111, the core layer 112 and the second skin layer 113 are integrally formed, and are not connected to each other in other manners, for example, the connection may be achieved without using an adhesive or the like, and only the foaming degrees of different regions need to be controlled to form the first skin layer 111, the core layer 112 and the second skin layer 113 with different structures, so that not only is the structural reliability and the firmness improved, but also the separation between the first skin layer 111, the core layer 112 and the second skin layer 113 is avoided, and the complexity of the manufacturing process can be reduced, and the first skin layer 111, the core layer 112 and the second skin layer 113 which are connected to each other can be simultaneously formed without additional process steps.

Compared with the existing scheme of bonding the formed shell, the existing shell formed by bonding the multilayer structure has the defect of limited shape, and can only be formed into a regular shape, such as a rectangular sheet body. The microcellular foam shell of the invention is formed into an integrally-formed part through microcellular foam injection molding, and can form structures of various shapes, namely regular-shaped parts or irregular-shaped parts. That is, the present invention can form uneven areas such as corners by the microcellular foam casing having the microcellular foam injection molded shape, thereby greatly improving the structural uniformity of the casing 10 of the sound generating apparatus 100 at various positions, and improving the appearance beauty and uniformity of the casing 10 of the sound generating apparatus 100 without additionally bonding other casing structures to the corners, and the like.

Alternatively, the first skin layer 111 and the second skin layer 113 have no pores therein, that is, the first skin layer 111 and the second skin layer 113 may be a compact structure without pores, and may prevent liquid and gas from passing through, so that the liquid and gas cannot pass through the microporous foam shell from both outer sides of the microporous foam shell, thereby playing a role in preventing water, dust and gas from passing through, and further protecting the structure housed in the shell 10, such as the sound generating unit 20 in the shell 10.

Alternatively, the first skin layer 111 and the second skin layer 113 may have pores therein, but the pore diameter of the pores is less than 0.5 μm, and since the pore diameter is small enough, it is still difficult for both liquid and gas to enter and exit the housing 10 through the pores, so that the waterproof and gas-permeation-preventing effects can be achieved, and the structure accommodated in the housing 10 can be protected.

It can be seen that the first skin layer 111, the second skin layer 113 and the core layer 112 can be integrally foamed, wherein the foaming ratio of the first skin layer 111 and the second skin layer 113 is lower than that of the core layer 112. Wherein, the closed cell foaming rate of the core layer 112 can be more than or equal to 90%.

In addition, the core layer 112 has a microcellular foamed structure, which is a closed-cell foamed structure having cells. It should be noted that in the foam structure, the gas exists in the foam in the form of cells, and in the closed-cell foam structure, the core layer 112 has an independent cell structure, and the inner cells are separated from the cells by a wall membrane and are not connected with each other. The closed-cell foam material has the advantages of excellent impact resistance, rebound elasticity, flexibility, waterproofness and the like.

The diameters of the cells are 0.5 μm to 30 μm, the open-cell ratio of the cells on the core layer 112 is less than 10%, that is, when the first skin layer 111 and/or the second skin layer 113 have cells, the diameters of the cells are larger than the diameters of the cells, and the ratio of the area of the open-cell area on any cross section on the core layer 112 to the total area of the cross section is less than 10%. For example, the area of one cross-section of the core layer 112 is 10cm ² The total area of the opening area on the cross section is less than 1cm ² . It should be noted that if the diameter of the cells is less than 0.5 μm, this will result inThe core layer 112 has a high density, so that the weight reduction effect of the microcellular foam casing is deteriorated. If the diameter of the cells is more than 30 μm, although a good weight reduction effect is obtained, a large negative effect is exerted on the mechanical properties, etc. of the microcellular foamed housing, for example, the flexural modulus is lowered, so that the microcellular foamed housing is liable to be deformed and fail in a reliability test. By controlling the pore diameter of the pores to be between 0.5 and 50 microns, the microporous foam shell can be ensured to have good mechanical properties and mechanical properties, and the lightweight effect is achieved, which is beneficial to reducing the weight of the shell 10 and the sound generating device 100 comprising the shell 10. Alternatively, the diameters of the cells are 0.5 μm, 1.5 μm, 2.5 μm, 3.0 μm, 10 μm, 20 μm, 30 μm, etc., which can ensure the shell 10 to have the advantages of light weight, high modulus, temperature resistance, etc.

It should be noted that the pore size may be an average pore size of the cells, that is, the pore size of each cell in the core layer 112 may be different. For example, in some embodiments, the cell size may be 0.5 μm to 5 μm, in which case the smallest cell size of the cells in the core layer 112 may be 0.5 μm and the largest cell size of the cells in the core layer 112 may be 5 μm.

Thus, according to the housing 10 of the sound generating apparatus 100 of the embodiment of the present invention, the integrally molded microcellular foam housing having the three-layer structure is provided, so that the first skin layer 111 and the second skin layer 113 have the characteristics of no pore or small pore diameter to play the role of preventing water and gas permeation, and the core layer 112 having the microcellular foam structure is used to reduce the weight of the housing 10, thereby reducing the weight of the housing 10. In addition, the engineering plastic has good temperature resistance, and can meet the high-temperature reliability requirement of the shell 10 of the sound generating device 100.

According to one embodiment of the present invention, the engineering plastic material includes at least one of poly 4 methyl-1-pentene (TPX), polypropylene (PP), syndiotactic Polystyrene (SPS), PA66, PA6, PA68, PA610, PA612, PA9, PA1010, PA1012, PA11, PA12, PA1212, PA1313, polyphthalamide (PPA), polyetherimide (PEI), polycarbonate (PC), polyoxymethylene (POM), polyphenylene oxide (PPO), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyphenylene Sulfide (PPs), polyarylate (PAR), polyether ether ketone (PEEK), and Liquid Crystal Polymer (LCP). Because the material has good temperature resistance, the microcellular foam shell prepared from the material can meet the high-temperature reliability requirement of the loudspeaker module.

According to an embodiment of the present invention, the raw material further includes a reinforcing agent, and the strength of the case 10 can be improved by using the reinforcing agent. The reinforcing agent comprises at least one of glass fiber, carbon fiber, basalt fiber and polymer fiber. Alternatively, the polymer fiber may be selected from aramid fiber, polyimide fiber, and the like. By using the fibrous material as the reinforcing agent, not only the strength of the housing 10 can be improved, but also the fibrous material can make the housing 10 less likely to be broken even if the housing 10 is slightly broken locally.

Wherein the density of the glass fiber material is generally 2.5g/cm ³ ～2.8g/cm ³ The glass fiber can include alkali-free glass fiber, medium-alkali glass fiber, high-strength glass fiber, alkali-resistant glass fiber, low-dielectric glass fiber and the like, and has the advantage of wide selection range.

Optionally, the feedstock further comprises a silane coupling agent. It should be noted that, because the difference between the surface energy of the glass fiber and the surface energy of the engineering plastic material is too large, the wettability and the dispersibility of the glass fiber in the engineering plastic material are poor, so the glass fiber may be surface-treated to improve the compatibility between the two, for example, a silane coupling agent may be treated on the surface of the glass fiber during production and processing. Further, the silane coupling agent used may include a methacryloxy silane coupling agent, a vinyl silane coupling agent, an alkyl silane coupling agent, a chloroalkyl silane coupling agent, and the like, and can improve the strength of the prepared housing 10.

Further, when carbon fibers are used as the reinforcing fibers, the density of the carbon fibers is generally 1.5g/cm ³ ～2.0g/cm ³ It can be seen that the density of the carbon fibers is less than that of the glass fibers. In addition, the reinforcing effect of the carbon fiber is better. It should be noted that the phases between the carbon fibers and the engineering plastic materialThe compatibility is poor, and optionally, during production and processing, a layer of polymer material is pre-impregnated with the carbon fibers to perform surface treatment on the carbon fibers, so that the compatibility between the carbon fibers and the engineering plastic material is improved, and the strength of the prepared shell 10 can be improved.

When the reinforcing fiber is basalt fiber, the basalt fiber has the advantage of high modulus, but the surface energy of the basalt fiber is relatively low, and optionally, during production and processing, the basalt fiber is subjected to surface treatment, so that the surface activity of the basalt fiber is improved, and the modulus of the prepared shell 10 can be improved.

When the reinforcing fiber is polymer fiber, the density of the polymer fiber is generally less than 1.5g/cm ³ The common polymer fibers can be aromatic polyamide fibers and polyimide fibers, and the polymer fibers have excellent temperature resistance and compatibility with engineering plastics, so that the shell 10 prepared from the polymer fibers has the temperature resistance.

According to one embodiment of the invention, the reinforcing agent is present in an amount of 10wt% to 40wt% based on the total weight of the feedstock, that is, the weight percentage of the reinforcing agent is 10wt% to 40wt%, inclusive. It should be noted that, when the mass fraction of the reinforcing agent is less than 10wt%, the reinforcing effect of the reinforcing agent on the engineering plastic material is small, which is likely to cause the mechanical property of the engineering plastic material to be low and the temperature resistance to be poor, i.e., the damage and failure of the prepared microcellular foamed shell are likely to be caused. When the weight percentage of the reinforcing agent is more than 40wt%, the density of the reinforcing agent is generally higher than that of the engineering plastic material, and the larger the weight percentage of the reinforcing agent is, the higher the density of the microcellular foamed shell is, and the purpose of light weight is not achieved. And with the increase of the weight fraction of the reinforcing agent, the melt viscosity of the engineering plastic material is increased, the melt index is reduced, and the injection molding of a thin-wall product, namely the injection molding of the shell 10 with a thin thickness is difficult. When the reinforcing agent accounts for 10wt% -40 wt% of the raw materials, the shell 10 has the advantages of good mechanical property, high temperature resistance and low density, that is, the requirement of lightening the sounding device 100 can be met, and the requirements of the sounding device 100 on mechanical property and high temperature resistance can be met. Optionally, the weight percentage of the reinforcing agent is 10wt%, 15wt%, 20wt%, 25wt%, 30wt% or 40wt%, etc., which can improve the mechanical properties and high temperature resistance of the obtained microcellular foamed shell, and also achieve the purpose of light weight, and also facilitate obtaining a microcellular foamed shell with a thinner thickness by injection molding.

According to an embodiment of the present invention, the raw material further includes a nano filler, and the nano filler includes at least one of silica, carbon black, clay, carbon nanotubes, calcium carbonate, cellulose, montmorillonite, alumina, graphene oxide, talc, mica powder, kaolin, wollastonite, diatomaceous earth, and titanium dioxide. It should be noted that, in the process of preparing the microporous foam shell, the nanofiller may induce the gas to form a gas core first, and the gas core may form bubbles, which is finally beneficial to forming the cells of the core layer 112, and is beneficial to realizing the lightweight of the shell 10.

Optionally, the raw material further comprises a coupling agent. The surface of the nano filler can be treated by a coupling agent, for example, a silane coupling agent and a titanate coupling agent, so that the compatibility of the nano filler and the engineering plastic material can be improved. Wherein, silica, clay, montmorillonite, aluminium oxide, talcum powder, mica powder, kaolin, wollastonite and diatomite can be treated by a silane coupling agent, and the used silane coupling agent comprises the following components: vinyltriethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-aminopropyltriethoxysilane. Wherein, the carbon black, the carbon nano tube, the calcium carbonate, the cellulose graphene, the graphene oxide and the titanium dioxide can be treated by titanate coupling agent.

In this embodiment, the nanofiller is treated by using the coupling agent, and molecules of the coupling agent simultaneously have a reactive group capable of being bonded with an inorganic material and a reactive group capable of being bonded with an organic material, so that the compatibility of the nanofiller with an engineering plastic material is improved, the bonding force between the nanofiller and the engineering plastic material is improved, the bonding force between the first skin layer, the core layer and the second skin layer is improved, and the firmness of the prepared shell 10 is improved.

According to one embodiment of the invention, the largest dimension of the outer contour of the nanofiller is ≦ 3 μm, that is to say the largest dimension in three dimensions of the nanofiller is not greater than 3 μm. It should be noted that if the size of the nanofiller is larger than 3 μm, the induction effect of forming the gas core is weak. When the maximum size of the outer contour of the nano filler is less than or equal to 3 mu m, the generation of gas nuclei can be effectively induced, and the foaming rate of the core layer is improved. By limiting the maximum size range of the outer contour of the nano filler, the micro-porous foaming structure is favorably formed in the engineering plastic material.

In addition, in the micro-foaming injection molding process, the nano filler can obviously reduce the cell diameter of the foaming material and increase the cell density of the foaming material. The smaller the diameter of the foam hole of the foaming material is, the smaller the loss of the mechanical property of the material is, and the deformation failure of the microcellular foaming shell caused by the loss of the mechanical property in the high-temperature reliability test process is avoided.

According to one embodiment of the invention, the amount of nanofiller is 0.1 to 3wt% based on the total weight of the feedstock, that is to say the weight percentage of nanofiller is 0.1 to 3wt%, inclusive of 0.1 and 3wt%. It should be noted that if the weight percentage of the nanofiller is less than 0.1wt%, agglomeration is liable to occur, and the effect of reducing the cell diameter of the foam becomes small, and it becomes difficult to form cells as desired. If the weight percentage of the nano filler is greater than 3wt%, the dispersion uniformity of the nano filler in the engineering plastic material is liable to be deteriorated, which may cause the defects of the foamed material of the core layer 112 to be increased and the mechanical properties to be deteriorated. When the mass fraction of the nano filler in the raw material is 0.1wt% -3 wt%, the nano filler can be uniformly distributed in the engineering plastic material in the micro-foaming injection molding process, which is beneficial to uniform distribution of cells in the core layer 112 and control of the pore diameter of the cells, so that the shell 10 has the advantage of small density, and the shell 10 can have excellent mechanical properties.

Wherein, the preferable mass percentage of the nano filler is 0.5wt% to 1.5wt%, at this time, not only the weight of the microcellular foamed shell can be reduced, but also the formation of cells is facilitated, and the mechanical property of the shell 10 is ensured. Alternatively, the nano filler may be present in the raw material in a mass fraction of 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, and the like.

According to one embodiment of the invention, the microcellular foamed casing has a density of 0.8g/cm ³ ～1.2g/cm ³ Including endpoint value of 0.8g/cm ³ And 1.2g/cm ³ . It should be noted that if the density of the microcellular foamed casing is less than 0.8g/cm ³ Will tend to result in a microcellular foamed shell of low strength; if the density of the microcellular foamed casing is more than 1.2g/cm ³ This would result in a heavier microcellular foam housing, thereby increasing the weight of the sound generating apparatus 100. When the density of the microcellular foam shell is 0.8g/cm ³ ～1.2g/cm ³ In this case, the housing 10 may have both advantages of high strength and low density, that is, not only the requirement of the sound generating device 100 for light weight can be satisfied, but also the requirement of the sound generating device 100 for strength can be ensured. Optionally, the microcellular foamed shell has a density of 0.8g/cm ³ 、0.9g/cm ³ 、1.0g/cm ³ 、1.15g/cm ³ 、1.20g/cm ³ And so on, the sound emission device 100 can be made to have both light weight and high strength.

According to one embodiment of the invention the flexural modulus of the microcellular foamed housing is ≧ 3GPa, i.e. the flexural modulus of the microcellular foamed housing is ≧ 3GPa. It should be noted that if the flexural modulus of the microcellular foam housing is less than 3.5GPa, the strength of the microcellular foam housing is likely to be insufficient, and the sound generating apparatus 100 assembled by the microcellular foam housing is likely to generate resonance. Therefore, the flexural modulus of the microcellular foam casing is not less than 3.5GPa, which is beneficial to improving the acoustic performance and mechanical performance of the sound generating device 100. When the flexural modulus is not less than 3.5GPa, the flexural modulus of the microcellular foam casing of the present embodiment can be made to satisfy the flexural modulus requirement of the casing 10 of the sound-emitting device 100. Alternatively, the flexural modulus of the microcellular foam casing may be 3GPa, 4GPa, 5GPa, 6GPa, 7GPa, 8GPa, 10GPa, or the like, and the structural strength of the microcellular foam casing may be made to satisfy the use requirements of the sound generating apparatus 100.

The testing principle of the flexural modulus of the microcellular foam shell refers to GB/T9341-2008, and the specific testing method is as follows: 2mm/min, taking a flat part with uniform thickness on the shell 10, wherein the width b of the sample is 5mm; the diameter of the pressure head is 2mm; when the thickness of the sample is less than 1mm, the test span is 5mm; when the thickness of the sample is between 1mm and 1.5mm, the test span is 6mm; when the thickness of the sample is between 1.5mm and 2mm, the test span is 7mm; 5 splines were tested and averaged.

According to one embodiment of the invention, the microcellular foamed casing has a heat distortion temperature of 130 ℃ or higher. Specifically, under the condition that the bending stress is 1.8MPa, the thermal deformation temperature of the microcellular foam shell is not less than 130 ℃, and the high-temperature reliability of the microcellular foam shell can be ensured. It should be noted that a heat distortion temperature of less than 130 ℃ will result in poor temperature resistance of the casing 10. The thermal deformation temperature of the microcellular foamed housing of the present embodiment is easily satisfied with the requirement of high temperature resistance of the housing 10 of the sound generating apparatus 100 by limiting the thermal deformation temperature of the microcellular foamed housing to not less than 130 ℃, so that it can be normally used in normal environments and some extreme environments.

The testing principle of the thermal deformation temperature can refer to GB/T1634.. 1-2004, and the specific testing method is as follows:

1) Taking a flat part with uniform thickness on the shell 10, wherein the length, width and height dimensions are 80 multiplied by 10 multiplied by 4mm, the span is 64mm, the bending stress is 1.8MPa, the heating rate is 120 ℃/h, and the standard deflection is 0.34mm;

2) When the length, width and height dimensions < (80 multiplied by 10 multiplied by 4 mm), the spline dimension can be selected from 15 multiplied by 5 multiplied by h (h is the thickness of the shell 10), the span is 10mm, the bending stress is 1.8MPa, the heating rate is 120 ℃/h, and the standard deflection calculation method comprises the following steps:

the calculation method refers to GB/T1634.1-2004.

According to an embodiment of the present invention, the case 10 includes a first sub-case and a second sub-case, the first sub-case is bonded to or integrally injection-molded with the second sub-case, the first sub-case is formed as a microcellular foamed case, and the second sub-case is formed by at least one of steel, aluminum alloy, copper alloy, titanium alloy, PP and a modified material thereof, PA and a modified material thereof, PET and a modified material thereof, PBT and a modified material thereof, PPs and a modified material thereof, PEI and a modified material thereof, PEEK and a modified material thereof, PEN and a modified material thereof, PPA and a modified material thereof, PC and a modified material thereof, SPS and a modified material thereof, TPX and a modified material thereof, POM and a modified material thereof, and LCP and a modified material thereof.

That is, as shown in fig. 1, the housing 10 of the sound generating device 100 according to the embodiment of the present invention may be assembled by a first sub-housing and a second sub-housing, and the two sub-housings may be connected by bonding or may be assembled by other methods such as injection molding. The first sub-shell is mainly made of a microporous foaming shell, the second sub-shell can be made of metal materials such as steel, aluminum alloy, copper alloy and titanium alloy, and can also be made of PP (polypropylene) and modified materials thereof, PA (polyamide) and modified materials thereof, PET (polyethylene terephthalate) and modified materials thereof, PBT (polybutylene terephthalate) and modified materials thereof, PPS (polyphenylene sulfide) and modified materials thereof, PEI (polyetherimide) and modified materials thereof, PEEK (polyether ketone) and modified materials thereof, PEN (polyethylene terephthalate) and modified materials thereof, PPA (PPA) and modified materials thereof, PC (polycarbonate) and modified materials thereof, SPS and modified materials thereof, TPX and modified materials thereof, POM (polyoxymethylene) and modified materials thereof, LCP (liquid Crystal Polymer terephthalate) and modified materials thereof, and the like.

According to the above embodiments, the casing 10 of the sound generating device 100 made of the engineering plastic material according to the embodiments of the present invention has the advantages of low density, high modulus, etc., and can satisfy the requirements of mechanical property, and light weight.

The invention also provides a sound generating device 100 comprising the housing 10 of the sound generating device 100 of any of the above embodiments. The sound generating device 100 further includes a sound generating unit 20 disposed in the housing 10, and sound generating performance of the sound generating device 100 is realized by performing electro-acoustic conversion through the sound generating unit 20. Wherein, the sound generating unit 20 may be a speaker unit. At least a part of the casing 10 of the sound generating device 100 is made of the microcellular foam casing according to any of the above embodiments, which not only can satisfy the acoustic performance of the sound generating device 100, but also can satisfy the design requirements of lightness, thinness and mechanical properties of the sound generating device 100, and improves the applicability of the sound generating device 100 in various electronic devices.

When the sound generating device 100 is manufactured by the housing 10 and the sound generating unit 20 according to the embodiment of the present invention, the housing 10 of the sound generating device 100 may be manufactured by a micro-foaming injection molding process, and the speaker unit, that is, the sound generating unit 20 is accommodated in the housing 10. The loudspeaker unit comprises a vibration system and a magnetic circuit system.

The housing 10 of the sound generating device 100 may include an upper housing 11 and a lower housing 12, and the speaker unit is first fixed to the upper housing 11 or the lower housing 12, and then the upper housing 11 and the lower housing 12 are welded together by ultrasonic welding or glue bonding, thereby completing the assembly of the sound generating device 100. Wherein the upper shell 11 may be composed entirely of the first sub-shell, or at least by the first sub-shell and the second sub-shell. The lower shell 12 may also be composed entirely of the first sub-shell, or at least by the first and second sub-shells.

The housing 10 of the sound generating device 100 may also include an upper shell 11, a middle shell and a lower shell 12, wherein the upper shell 11 is connected with the lower shell 12 through the middle shell. At least a part of at least one of the upper, middle and

lower shells

11, 12 is made of a microcellular foamed shell, i.e., the entirety of at least one of the upper, middle and

lower shells

11, 12 is made of a microcellular foamed shell, and a part of at least one of the upper, middle and

lower shells

11, 12 is made of a microcellular foamed shell.

Optionally, the sound generating device 100 extrudes and granulates the engineering plastic material, the reinforcing agent and the nano filler by using a twin screw during preparation, and then forms the microcellular foamed shell by using a microcellular foam injection molding process.

For example, the production is carried out by adopting a twin-screw modified granulation process, the engineering plastic resin and the nano filler are uniformly mixed by a high-speed mixer, then the mixture is added into a main feeding port of a twin-screw extruder, after the resin is melted, the reinforcing agent is added into a side feeding port, and then the mixture is uniformly sheared and mixed in the extruder, and then the extrusion granulation is carried out. It should be noted that, when the reinforcing agent is made of fiber material, the fiber material can be added after the plastic particles are melted because of its large length-diameter ratio and general shear resistance, so as to effectively reduce the damage of the fiber material, thereby improving the reinforcing effect of the fiber on the material.

Because the surface energy difference between the reinforcing agent and the engineering plastic material is large, the reinforcing agent can be subjected to surface treatment, and the compatibility of the reinforcing agent and the engineering plastic material is improved. The surface treatment method can be used for surface modification through a coupling agent, for example, the glass fiber and the nano filler can be modified through vinyl triethoxysilane, vinyl trimethoxy silane, gamma-methacryloxypropyl trimethoxysilane, gamma-aminopropyl trimethoxysilane and gamma-aminopropyl triethoxysilane, so that the bonding force between the reinforcing agent and the engineering plastic material is improved.

Optionally, the engineering plastic material particles added with the reinforcing agent and the nano filler are added into a micro-foaming injection molding machine, and after the plastic particles are melted, N is added by using high-pressure equipment ₂ And or CO ₂ Injecting gas into the plastic melt, and then injecting the gas into a mold to form the microcellular foam shell.

The invention further provides an electronic device, which comprises the sound generating device 100 of any one of the above embodiments. The electronic device may be a mobile phone, a notebook computer, a tablet computer, a VR (virtual reality) device, an AR (augmented reality) device, a TWS (true wireless bluetooth) headset, a smart speaker, or the like, which is not limited in this respect.

Since the housing 10 of the sound generating device 100 according to the above-described embodiment of the present invention has the above-described technical effects, the sound generating device 100 and the electronic device according to the embodiment of the present invention also have the corresponding technical effects, that is, the housing 10 of the sound generating device 100 has lighter weight while meeting the requirements of mechanical performance and mechanical performance, so as to achieve the light weight of the electronic device product.

The housing 10 of the sound generating device 100 of the present invention will be described in detail with reference to specific examples and comparative examples.

Comparative example 1

In the present comparative example, the speaker module was assembled from a housing and a speaker unit. When the shell is prepared, 80wt% of PC is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, and the shell which is formed into a single-layer structure is manufactured by adopting a common injection molding process after modified granulation is carried out by a double-screw extruder.

Comparative example 2

In the present comparative example, the speaker module was assembled from a housing and a speaker unit. The shell is prepared by adopting 76wt% of PC as a matrix resin, adding 20wt% of glass fiber as a reinforcing agent and 4wt% of trihydrazinotriazine as a foaming agent, modifying and granulating through a double-screw extruder, and then adopting a common injection molding process to manufacture the shell with a single-layer structure.

Comparative example 3

In this comparative example, the speaker module was assembled from a housing and a speaker unit. The shell is prepared by adopting 80wt% of PA66 as a matrix resin, adding 20wt% of glass fiber as a reinforcing agent, modifying and granulating through a double-screw extruder, and then adopting a common injection molding process to manufacture the shell with a single-layer structure.

Comparative example 4

In this embodiment, the speaker module is assembled by the housing and the speaker unit. When the shell is prepared, 80wt% of PPA is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, and the shell which is formed into a single-layer structure is manufactured by adopting a common injection molding process after being modified and granulated by a double-screw extruder.

Comparative example 5

In this embodiment, the speaker module is assembled by the housing and the speaker unit. When the shell is prepared, 80wt% of PEI is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, and after modification and granulation by a double-screw extruder, the shell which is formed into a single-layer structure is manufactured by adopting a common injection molding process.

Example 1

In the present embodiment, the speaker module is assembled by the housing 10 and the speaker unit. When the shell is prepared, 79.9wt% of PC is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, 0.1wt% of nano-silica is used as a nano-filler, and after the modification and granulation are carried out by a double-screw extruder, the shell 10 is manufactured and formed by adopting a micro-foaming injection molding process. The housing 10 has a three-layer structure including a first skin layer 111, a core layer 112, and a second skin layer 113.

Example 2

In the present embodiment, the speaker module is assembled by the housing 10 and the speaker unit. When the shell is prepared, 79wt% of PC is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, 1wt% of nano silica is used as a nano filler, and after modification and granulation are carried out by a double-screw extruder, the shell 10 is manufactured by adopting a micro-foaming injection molding process. The housing 10 has a three-layer structure including a first skin layer 111, a core layer 112, and a second skin layer 113.

Example 3

In the present embodiment, the speaker module is assembled by the housing 10 and the speaker unit. When the shell is prepared, 78.5wt% of PC is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, 1.5wt% of nano-silica is used as a nano-filler, and after the modification and granulation are carried out by a double-screw extruder, the shell 10 is manufactured by adopting a micro-foaming injection molding process. The housing 10 has a three-layer structure including a first skin layer 111, a core layer 112, and a second skin layer 113.

Example 4

In the present embodiment, the speaker module is assembled by the housing 10 and the speaker unit. When the shell is prepared, 78wt% of PA66 is used as matrix resin, 20wt% of glass fiber is added to be used as a reinforcing agent, 2wt% of nano mica sheets are used as nano fillers, and after the materials are modified and granulated by a double-screw extruder, the shell 10 is manufactured by adopting a micro-foaming injection molding process. The housing 10 has a three-layer structure including a first skin layer 111, a core layer 112, and a second skin layer 113.

Example 5

In the present embodiment, the speaker module is assembled by the housing 10 and the speaker unit. When the shell is prepared, 77wt% of PPA is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, 3wt% of nano calcium carbonate is used as nano filler, and after the modification and granulation by a double screw extruder, the shell 10 is manufactured by adopting a micro foaming injection molding process. The housing 10 has a three-layer structure including a first skin layer 111, a core layer 112, and a second skin layer 113.

Example 6

In the present embodiment, the speaker module is assembled by the housing 10 and the speaker unit. When the shell is prepared, 79.9wt% of PEI is used as matrix resin, 20wt% of glass fiber is added as a reinforcing agent, 0.1wt% of carbon nano tube is used as nano filler, and after modification and granulation are carried out by a double-screw extruder, the shell 10 is manufactured by adopting a micro-foaming injection molding process. The housing 10 has a three-layer structure including a first skin layer 111, a core layer 112, and a second skin layer 113.

For comparison, the formulation and molding process of the raw materials of comparative examples 1 to 5 and examples 1 to 6 are shown in table 1 below.

TABLE 1 Material composition and Molding Process

The materials and products of comparative examples 1 to 5 and examples 1 to 6 were tested as follows.

(1) The shells prepared in examples 1 to 6 and the shells 10 prepared in comparative examples 1 to 5 were subjected to cell average pore size, density, flexural modulus, heat distortion temperature and izod notched impact strength tests, and the test results are shown in table 2 below.

TABLE 2 comparison of Properties

As can be seen from Table 1, the density of the housing material of comparative example 1, which is obtained by using the common injection molding process in comparative example 1 in combination with Table 2, is 1.35g/cm ³ That is, the weight of the case obtained by the general injection molding process in comparative example 1 was large.

It can be seen from table 1 that comparative example 2 employs a mold foaming process. As can be seen from Table 2, the average cell diameter of the outer shell of comparative example 2 is 150 μm to 220 μm, and the average cell diameter of the outer shell of comparative example 2 is larger than that of examples 1 to 6Is relatively large. In addition, comparative example 2 had a density of 1.02g/cm ³ The flexural modulus of the outer shell is 1.12MPa, and the flexural modulus of the outer shell of the comparative example 2 is reduced sharply, so that the requirement of the product cannot be met.

As can be seen from table 1 and table 2, in comparative example 3, PA66 is used as the matrix resin, in comparative example 4, PPA is used as the matrix resin, and in comparative example 5, PEI is used as the matrix resin, no cells exist in the obtained shell, and the shell has a large weight, which does not meet the requirement of light weight.

As can be seen from table 1, examples 1 to 3 all used PC as the matrix resin, and the reinforcing agents were contained in the same amounts and the nanofillers were contained in different amounts in examples 1 to 3. Specifically, the nanofiller of example 1 was at a minimum and the nanofiller of example 3 was at a maximum. As can be seen from Table 2, the average cell diameter of the cells of example 1 is 10 μm to 30 μm, the average cell diameter of the cells of example 2 is 1 μm to 20 μm, and the average cell diameter of the cells of example 3 is 1 μm to 15 μm. Further, as can be seen from Table 2, the flexural modulus of example 1 was 4.7MPa, the flexural modulus of example 2 was 5.1MPa, and the flexural modulus of example 3 was 5.2MPa. The notched Izod impact strength of example 1 was 9kJ/m ² The notched Izod impact strength of example 2 was 11kJ/m ² The notched Izod impact strength of example 3 was 14kJ/m ² . It can be seen that in examples 1, 2 and 3, as the content of the nano silica filler increases, the average diameter of the cell pores decreases, the flexural modulus increases, the notched impact strength increases, and the toughness improves.

As can be seen from table 1, both example 4 and comparative example 3 use PA66 as a matrix resin and glass fibers as a reinforcing agent, except that nano-mica sheets are used as a nano-filler in example 4 and no nano-filler is contained in comparative example 3. Example 5 and comparative example 4 both used PPA as the matrix resin and glass fibers as the reinforcing agent, except that nanocalcium carbonate was used as the nanofiller in example 5 and no nanofiller was included in comparative example 4. In example 6 and comparative example 5, PEI was used as a matrix resin and glass fiber was used as a reinforcing agent, except that carbon nanotubes were used as a nanofiller in example 6 and no nanofiller was included in comparative example 5. And the micro-foaming injection molding process is adopted in examples 4 to 6, and the general injection molding process is adopted in comparative examples 3 to 5.

As can be seen from Table 2, the flexural modulus of example 4 was 5.2MPa, the flexural modulus of example 5 was 4.8MPa, and the flexural modulus of example 6 was 4.7MPa. The flexural modulus of comparative example 3 was 6.9MPa, the flexural modulus of example 5 was 5.5MPa, and the flexural modulus of example 6 was 5.5MPa. The density of the case 10 of example 4 was 1.09g/cm ³ The density of the case 10 of example 5 was 1.1g/cm ³ The density of the case 10 of example 6 was 1.17g/cm ³ . It can be seen that, in examples 4, 5 and 6, the housing 10 is prepared by using the micro-foaming process, and compared with the housings of comparative examples 3, 4 and 5, the flexural modulus is not significantly reduced, but the density is significantly reduced, so that the aim of light weight can be achieved on the basis of meeting the requirement of reliability verification of the speaker module.

(2) The housings prepared in examples 1 to 6 and the housing 10 prepared in comparative examples 1 to 5 were assembled with a single speaker to obtain different speaker modules, and each speaker module was tested for drop reliability, high temperature and high humidity reliability, high power reliability, and high and low temperature cycle reliability, and the test results are shown in table 3 below.

TABLE 3 comparison of reliability results

The reliability test conditions in table 3 are as follows:

the reliability test conditions were as follows:

drop reliability: the shell falls for 200 times per wheel from the height of 1.5m, and 3 wheels are carried out in total; and judging the shell is not damaged or cracked according to the judgment standard, and judging the shell is OK if the shell is not cracked, or judging the shell is NG if the shell is not cracked.

High-temperature high-humidity reliability test: the loudspeaker module is placed in an environment with the temperature of 85 ℃ and the humidity of 85 percent, operates for 72 hours at rated voltage of 1.2 times, and tests the size variation of the shell of the loudspeaker module; and (4) judging standard: if the variation in the enclosure dimension of the speaker module exceeds 5s (s is a filament, and 10 μm is 1 s), it is judged NG, and if the variation in the enclosure dimension is less than 5s, it is judged OK.

High power reliability: the loudspeaker module is placed at normal temperature and runs for 96 hours at 1.2 times of rated power; and (4) judging standard: the size variation of the shell of the loudspeaker module is less than 5s, the judgment is OK when no obvious noise exists in the audition, the size variation is more than 5s, or the judgment is NG when the noise exists in the audition.

High and low temperature cycle reliability: placing the loudspeaker module in an environment at minus 30 ℃ for 2h, then transferring to an environment at 80 ℃ for placing for 2h, and repeating the operation for 30 times to obtain the size variation of the shell of the loudspeaker module; and (3) judging standard: if the variation in the enclosure dimension of the speaker module exceeds 5s (s is a filament, and 10 μm is 1 s), it is judged NG, and if the variation in the enclosure dimension is less than 5s, it is judged OK.

As can be seen from a combination of tables 2 and 3, comparative example 2 fails to satisfy drop reliability, high temperature and high humidity reliability, high power reliability, and high and low temperature cycle reliability. Although comparative example 1, comparative example 3, comparative example 4, and comparative example 5 can satisfy the reliability verification requirement, the densities of comparative example 1, comparative example 3, comparative example 4, and comparative example 5 are higher. Further, although comparative example 2 has a lower density, the decrease in flexural modulus is severe and the notched impact strength is low, resulting in a case that falls during reliability and is liable to fail, and the case dimensional deformation is severe, resulting in a speaker failure.

As can be seen from table 2, the density of the housing 10 is significantly reduced in examples 1 to 6, but the flexural modulus is reduced less, and the reliability verification requirement can still be satisfied.

Therefore, in comparative examples 1 to 5, the glass fiber is added into the PC material, and the mass of the housing of the speaker module is large due to the high density of the glass fiber, so that the overall weight of the electronic device is too large, and the use experience of consumers is affected. And after the glass fiber is added into the PC material, the toughness of the PC material is reduced while the rigidity of the PC material is improved, so that the PC material can be cracked and failed in the falling reliability. The microcellular foam shell in the embodiment of the invention is made of engineering plastic materials, and the engineering plastic materials comprise the first skin layer 111, the core layer 112 and the second skin layer 113, so that the waterproof effect can be improved, the density can be reduced, and the weight of the loudspeaker module can be reduced. In addition, the nano filler with specific content can be added into the engineering plastic material, so that the pore diameter of the pores of the microcellular foamed shell is effectively reduced, the toughness of the shell 10 is improved, and the impact strength of the microcellular foamed shell is improved. In addition, the prepared microcellular foam shell also has the advantages of small modulus reduction, low density, high toughness, capability of meeting the requirements of light weight and reliability of a loudspeaker module and the like.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. The casing of the sound production device is characterized in that at least one part of the casing is a microcellular foam casing, raw materials of the microcellular foam casing comprise engineering plastic materials, the microcellular foam casing is an integrally formed part formed by foaming and injection molding the raw materials, and the microcellular foam casing comprises a first skin layer, a core layer and a second skin layer which are sequentially stacked;

2. The housing of a sound emitting device according to claim 1, wherein the engineering plastic material comprises at least one of poly 4 methyl-1-pentene, polypropylene, syndiotactic polystyrene, PA66, PA6, PA68, PA610, PA612, PA9, PA1010, PA1012, PA11, PA12, PA1212, PA1313, PPA, PEI, polycarbonate, polyoxymethylene, polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyarylate, polyetheretherketone, liquid crystal polymer.

3. The housing of claim 1, wherein the feedstock further comprises a reinforcing agent, the reinforcing agent comprising at least one of glass fibers, carbon fibers, basalt fibers, and polymer fibers.

4. The housing of claim 3, wherein the enhancer is present in an amount of 10wt% to 40wt% based on the total weight of the raw material.

5. The casing of the sound generating apparatus according to claim 1, wherein the raw material further comprises a nano filler, and the nano filler comprises at least one of silica, carbon black, clay, carbon nanotubes, calcium carbonate, cellulose, montmorillonite, alumina, graphene oxide, talc, mica powder, kaolin, wollastonite, diatomite, and titanium dioxide.

6. The housing of the sound generating apparatus as claimed in claim 5, wherein the outer contour of the nano-filler has a maximum size of 3 μm or less.

7. The casing of the sound generating apparatus according to claim 5, wherein the nano filler accounts for 0.1wt% to 3wt% of the raw material.

8. The housing of a sound emitting device of claim 1, wherein the microcellular foamed housing has a density of 0.8g/cm ³ ～1.2g/cm ³ 。

9. The casing of the sound generating apparatus according to claim 1, wherein the microcellular foamed casing has a flexural modulus of 3GPa or more.

10. The casing of the sound generating apparatus as claimed in claim 1, wherein the microcellular foamed casing has a heat distortion temperature of 130 ℃ or more.

11. The housing of a sound emitting device according to any one of claims 1 to 10, wherein the housing comprises a first sub-housing and a second sub-housing, the first sub-housing is bonded to or integrally injection-molded with the second sub-housing, the first sub-housing is formed as the microcellular foamed housing, and the second sub-housing is manufactured by at least one of steel, aluminum alloy, copper alloy, titanium alloy, PP and its modified material, PA and its modified material, PET and its modified material, PBT and its modified material, PPs and its modified material, PEI and its modified material, PEEK and its modified material, PEN and its modified material, PPA and its modified material, PC and its modified material, SPS and its modified material, TPX and its modified material, POM and its modified material, and LCP and its modified material.

12. A sound generating device, comprising:

a housing for a sound emitting device according to any one of claims 1-11.

13. An electronic device characterized by comprising the sound emitting apparatus according to claim 12.